I wrote:
> Bruno THOMAS <bthomas(at)alea(dot)fr> writes:
>> My problem is that when I tried to make a dump of the copied DB for a
>> new backup I've had the following error :
>> pg_dump: query to obtain list of tables failed: ERROR: Relation
>> pg_class does not have attribute 1
> Reindexing pg_class might help.
On second thought, that symptom sounds more like a problem in the
pg_attribute indexes. Probably what you want to do is REINDEX DATABASE
to force recreation of all the system-table indexes ...
regards, tom lane